Back again, here's where the ride really gets started. Not as many references as the last chapter, but here we go!
Momotaro-san
Firstly, a video of the song they were imitating in the hallway:
From Wikipedia:
"Momotarō (桃太郎, "Clam Peach Boy") is a popular hero of Japanese folklore originating from Okayama Prefecture. His name translates as Peach Tarō, a common Japanese masculine name, and is often translated as Clam Peach Boy. Momotarō is the title of various books, films and other works that portray the tale of this hero."
The Mamotaro variation must be some play on words, I'm not sure though.
Nakamura Mondo
Like I mentioned in the chapter, Nakamura Mondo is the protagonist of Hissatsu Shigotonin, which this article from Giant Bomb describes as "focus[ing] on a group of ordinary "work people" who live double lives as assassins. It is an alternate Feudal Japan history (1603-1863) featuring fictional characters with elements of a parallel world."
Not sure to what end they were referencing him in the panel to be honest, but I'm sure it was a compliment.
Paradise Galaxy
Here's the music video for the song they were singing at the end:
Rereading through those last few pages with that music playing, mmmmm. Actually took me a second pass-through through the chapter before I thought to find the song.
Anything Else?
Not this time!
And that's Chapter 2. Catch you guys tomorrow.